Breast cancer is classified and managed on the basis of histological examination and size of the tumor, and whether spread has occurred to ancillary lymph nodes, to estimate the risk of future distant metastasis. About 75% of women have hormone receptor positive, node negative cancer at diagnosis and are usually treated with anti-hormonal therapies, such as tamoxifen or an aromatase inhibitor. An important question for patients and physicians alike is whether adjuvant chemotherapy should also be given to decrease the risk of disease recurrence or metastasis. Gene expression profiling of RNA extracted from a fixed section or biopsy specimen, used in conjunction with other clinical information, can help determine a woman’s risk for distant metastasis and in the selection of appropriate treatments.

Celera has identified a panel of gene expression markers predictive of risk for metastasis in breast cancer and developed another set of gene expression markers that provides an assessment of estrogen receptor and progesterone receptor status along with likely response to Herceptin® treatment.